/*
    base64.cpp and base64.h

    based on : http://www.adp-gmbh.ch/cpp/common/base64.html
*/

#include <nb++/Base64.hpp>

using namespace std;

static const std::string base64_chars =
    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    "abcdefghijklmnopqrstuvwxyz"
    "0123456789+/";

static inline bool is_base64(unsigned char c)
{
    return (isalnum(c) || (c == '+') || (c == '/'));
}

void nbpp::base64_encode( istream &is, ostream &os )
{
    int i = 0;
    unsigned char char_array_3[3];
    unsigned char char_array_4[4];

    while( true ) {
        unsigned char ch = is.get();

        if( is.eof())
            break;

        char_array_3[i++] = ch;

        if (i == 3) {
            char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
            char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);
            char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);
            char_array_4[3] = char_array_3[2] & 0x3f;

            for(i = 0; (i < 4) ; i++)
                os.put( base64_chars[char_array_4[i]] );

            i = 0;
        }
    }

    if( i ) {
        for(int j = i; j < 3; j++)
            char_array_3[j] = '\0';

        char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
        char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);
        char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);
        char_array_4[3] = char_array_3[2] & 0x3f;

        for (int j = 0; (j < i + 1); j++)
            os.put( base64_chars[char_array_4[j]] );

        while((i++ < 3))
            os.put( '=' );
    }
}

void nbpp::base64_decode( istream &is, ostream &os )
{
    int i = 0;
    int j = 0;
    unsigned char ch,
        char_array_4[4],
        char_array_3[3];

    ch = is.get();
    while ( !is.eof() && ch != '=' && is_base64( ch )) {
        char_array_4[i++] = ch;
        if (i == 4) {
            for (i = 0; i <4; i++)
                char_array_4[i] = base64_chars.find(char_array_4[i]);

            char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
            char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
            char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];

            for (i = 0; (i < 3); i++)
                os.put( char_array_3[i] );

            i = 0;
        }
        ch = is.get();
    }

    if (i) {
        for (j = i; j <4; j++)
            char_array_4[j] = 0;

        for (j = 0; j <4; j++)
            char_array_4[j] = base64_chars.find(char_array_4[j]);

        char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
        char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
        char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];

        for (j = 0; (j < i - 1); j++)
            os.put( char_array_3[j] );
    }
}
